承压状态下氟橡胶O型密封圈耐酸性介质腐蚀性能

通过考察自由状态及承压状态下的三种氟橡胶O型密封圈在酸性介质中腐蚀前后的几何尺寸、力学性能以及形貌的变化,对其耐酸性介质腐蚀性能做出了综合评价。结果表明:腐蚀后,氟橡胶O型密封圈的拉伸强度、拉断伸长率、硬度减小,几何尺寸发生变化;O型密封圈在承压状态下的腐蚀程度比自由状态下的轻;在承压状态下,液相腐蚀比气相腐蚀轻,而自由状态下则相反;腐蚀后O型密封圈会产生塑性变形、局部鼓泡、开裂等现象。

固体火箭发动机喷管橡胶堵盖承压状态仿真方法研究

针对固体火箭发动机喷管橡胶堵盖的受力状态,提出了一种基于Abaqus仿真建模及有限元仿真计算方法。通过橡胶堵盖组成材料(橡胶及夹布)应力-应变曲线及数据拟合,归纳出选择材料本构时应注意的问题;根据堵盖的实际产品状态、结构形态,提出了相关假设,建立了一种简化的有限元模型,并对某固体火箭发动机橡胶堵盖0.3 MPa的承压工况进行了有限元仿真计算。计算结果表明,夹布所承受载荷远高于橡胶部分,橡胶受力最大区域集中在内表面根部。经试验验证,仿真结果误差为5.3%,满足固体火箭发动机喷管橡胶堵盖的设计计算与分析要求。文中提出的建模方法为后续对固体火箭发动机喷管橡胶堵盖的打开及橡胶堵盖破坏过程的演化规律研究奠定了坚实的基础。

承压状态下邻近区域异种金属焊接方法研究与设计

以开利冷媒蒸发器的焊接接头为例,通过分析承压状态下异种金属的可焊性和焊接特点,以及共焊时容易出现的问题,确定合理的焊接工艺和顺序,通过实验验证焊接工艺的可行性和焊接接头的稳定性,确保得到良好的焊接机械性能。

承压状态下拱形可缩支架的现场修复技术

根据井下拱形可缩支架的损坏情况,先对巷道剁底扩帮,再利用单体液压支柱对损坏柱腿复位修复,既经济安全,又方便快速,效果良好。

模拟井筒工况下四丙氟橡胶O型圈腐蚀损伤研究

采用高温高压釜和自主设计的O型圈承压状态模拟装置模拟某高含CO_2介质天然气生产井井筒工况,在总压30 MPa、CO_2分压0.5MPa、温度140℃的条件下,分别在承压状态下和自由状态下对四丙氟橡胶O型圈进行了高温高压腐蚀实验。以O型圈试样的拉伸、硬度和压缩永久变形为考察指标,分析了腐蚀前后试样的力学性能损伤规律。研究结果表明,四丙氟橡胶O型圈在模拟工况下服役后力学性能下降,承压状态下橡胶材质的腐蚀损伤比自由状态的损伤程度小,气相环境中的腐蚀比液相环境严重,实验结果呈现出较好的规律性,建议将模拟井筒承压状态下橡胶材质的力学性能衰减程度作为腐蚀损伤的主要考察指标进行材质优选。

高温高压高含CO2环境下两种氟橡胶密封可靠性评价

目的研究两种氟橡胶O型圈在总压为25 MPa,CO2体积分数为5%,温度为120℃,液相介质Cl‒质量浓度为7000 mg/L的高温高压高含CO2工况下的密封可靠性。方法通过高温高压釜模拟井下实际工况,采用自研橡胶O型圈密封装置实现试样的承压状态,以物理性能、腐蚀形貌和抗渗透性能为考察指标,对两种氟橡胶O型圈的耐蚀性能和密封性能进行测试评价。结果氟硅橡胶O型圈在承压状态下腐蚀后,拉伸强度由18.1 MPa下降为13.4 MPa,拉断伸长率由172.8%下降为151.9%。AFLAS橡胶O型圈在承压状态下腐蚀后,拉伸强度由21 MPa下降为14.6 MPa,拉断伸长率由277%下降为212.3%,硬度从84HA下降为75.5HA,表面破损严重。两种橡胶O型圈抗渗透性能随压差增大、温度上升而减弱。结论承压状态下,两种橡胶O型圈性能衰减程度低于自由状态,氟硅橡胶O型圈在承压状态下表现出更好的密封可靠性。

工作面前方承压抽采钻孔瓦斯渗透规律及其层理效应研究

通过在义煤集团新安煤矿14171采煤工作前方布置与层理方向呈不同角度的3个瓦斯抽采钻孔,考察其瓦斯抽放浓度、流量、抽放纯量指标来揭示随工作面推进过程中钻孔不同承压状态下的瓦斯渗透规律;建立数值模型分别对3个抽采钻孔的瓦斯渗透率进行模拟,模拟结果与现场考察较为相似。研究结果表明:工作面前方7~11 m为瓦斯抽采效果最好的区域,且与煤层层理呈平行角度布置钻孔瓦斯效果最佳,工作面前方4~6 m为瓦斯抽采设备拆除的合理区域。

Research on Ecological Carrying Pressure in the Greater Dunhuang Region based on the Relationship between Supply and Consumption

The Greater Dunhuang Region has experienced ecological degradation in the past 100 years caused by human factors such as ecological immigration, expansion of arable land, and the construction of reservoirs. At present, through the restoration of various ecological projects, the progress of ecological deterioration has slowed down. Ensuring that the development and construction of the Greater Dunhuang Region Cultural Tourism Economic Circle does not threaten ecological security is the top priority of the regional sustainable development plan. Based on the balance between supply and consumption of the ecosystem, this study assesses the pressure of ecological consumption in the Greater Dunhuang Region, and analyzes the patterns and trends in the ecological carrying status. The results reveal three important aspects of the ecological carrying pressure in this Region.(1) After 2000,the ecological supply in the Greater Dunhuang Region experienced a fluctuating growth trend. In the entire ecosystem, the farmland ecosystem provides more than 55% of the ecological supply, and areas with relatively high supply capacity are concentrated in a small number of valleys.(2) The Greater Dunhuang Region is under greater production pressure and there is less pressure from living consumption. The production consumption intensity has exceeded the ecological supply since 2014. The production and consumption structure of the Greater Dunhuang Region is dominated by animal husbandry production and consumption, accounting for more than 65% of the total production and consumption.(3) The Greater Dunhuang Region has been in a state of rich and surplus from 2000 to 2017. However, Dunhuang City turned into a surplus state in 2017 due to the pressure of the fast-growing tourist population. The Greater Dunhuang Region urgently needs to alleviate the ecological pressure through the development of eco-friendly industries. It is necessary to develop an ecological protection resource utilization model that focuses on the development of ecological and cultural services in pastoral areas to ease the pressure on the ecosystem from animal husbandry production.

Temporal and Spatial Dynamics Analysis of Grassland Ecosystem Pressure in Kazakhstan

Affected by climate change and policy factors,Kazakhstan is the country with the most severe ecological degradation and grassland conflicts in Central Asia.Therefore,studying the state of grassland carrying resources in Kazakhstan is particularly important for understanding the responses of grassland ecosystems to climate change and human activities.Based on Kazakhstan's remote sensing data and animal husbandry statistics,this study analyzes the patterns of changes in grassland ecosystems in Kazakhstan based on the supply and consumption of these ecosystems.The results show that:1)From 2003 to 2017,the number of livestock raised in Kazakhstan showed a trend of sustained and steady growth.Due to freezing damage,the scale of livestock farming decreased in 2011,but a spatial difference in the livestock farming structure was not obvious.2)The fluctuation of grassland supply in Kazakhstan has increased,while the consumption due to animal husbandry has also continued to increase,resulting in an increasing pressure on the grassland carrying capacity.3)Between 2003 and 2017,the overall grassland carrying status of Kazakhstan have been abundant,but the grassland carrying pressure index has shown a steadily increasing trend,the grassland carrying pressure is growing,and it is mainly determined by grassland productivity.The greater pressure in lower Kyzylorda state,the southern Kazakhstan state of the cultivated land and the northern Kazakhstan state has gradually expanded to include the agro-pastoral zone and the semi-desert zone.